Terminal device, communication method, and integrated circuit

ABSTRACT

A terminal device and a base station device efficiently communicate with each other. The terminal device includes a transmission unit configured to repeatedly transmit uplink control information including at least one CQI using a plurality of PUCCHs in a plurality of subframes, in a case where uplink control information is transmitted in the PUCCH in an initial subframe included in the plurality of subframes, based on whether the uplink control information includes an HARQ-ACK, (i) the uplink control information is transmitted using the PUCCH in a first subframe included in the plurality of subframes, or (ii) the uplink control information is not transmitted in the first subframe included in the plurality of subframes.

TECHNICAL FIELD

The present invention relates to a terminal device, a communication method, and an integrated circuit.

This application claims priority based on JP 2015-227483 filed on Nov. 20, 2015, the contents of which are incorporated herein by reference.

BACKGROUND ART

In the 3rd Generation Partnership Project (3GPP), a radio access method and a radio network for cellular mobile communications (hereinafter referred to as “Long Term Evolution (LTE)”, “Evolved Universal Terrestrial Radio Access (EUTRA)”, or “Evolved Universal Terrestrial Radio Access Network (EUTRAN)”) have been studied. In LTE, a base station device is also referred to as an evolved NodeB (eNodeB), and a terminal device is also referred to as User Equipment (UE). LTE is a cellular communication system in which multiple areas each covered by the base station device are deployed to form a cellular structure. A single base station device may manage multiple cells.

LTE supports a Time Division Duplex (TDD). LTE that employs the TDD scheme is also referred to as TD-LTE or LTE TDD. In TDD, uplink signals and downlink signals are time division multiplexed. Furthermore, LTE supports a Frequency Division Duplex (FDD).

In LTE, Downlink Control Information (DCI) is transmitted using a Physical Downlink Control CHannel (PDCCH) and an Enhanced Physical Downlink Control CHannel (EPDCCH). DCI is used for scheduling of a Physical Downlink Shared CHannel (PDSCH) in a cell.

A technique for transmitting a Machine type communication Physical Downlink Control CHannel (MPDCCH) in multiple subframes has been studied in the 3GPP to improve a downlink cell coverage (NPL 1). In addition, a technique for transmitting a Physical Uplink Control CHannel (PUCCH) in multiple subframes has been studied in the 3GPP to improve an uplink cell coverage (NPL 2).

CITATION LIST Non-Patent Documents

-   [NON-PATENT DOCUMENT 1] NPL 1: “R1-153458 WF on principle of M-PDCCH     search space design”, 3GPP TSG RAN WG1 #81, 25th-29th, May 2015. -   [NON-PATENT DOCUMENT 2] NPL 2: “R1-153571 Way Forward on PUCCH     enhancement for MTC”, 3GPP TSG RAN WG1 #81, 25th-29th, May 2015.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

According to the present invention, provided are a terminal device capable of efficiently communicating with a base station device using multiple physical channels included in multiple subframes, a communication method used by the terminal device, and an integrated circuit mounted on the terminal device.

Means for Solving the Problems

(1) According to some aspects of the present disclosure, the following measures are provided. Specifically, according to a first aspect of the present invention, a terminal device includes: a reception unit configured to monitor an MPDCCH in a search space corresponding to a plurality of subframes; and a medium access control layer processing unit configured to perform a DRX functionality for controlling monitoring of the MPDCCH. The medium access control layer processing unit starts or restarts a drx-InactivityTimer in a next subframe of a last subframe in the search space in a case that the MPDCCH indicates initial transmission, the medium access control layer processing unit starts an HARQ RTT timer in a case that the MPDCCH indicates downlink transmission, the HARQ RTT timer is set based on the number of times a PUCCH is repeatedly transmitted, a drx-RetransmissionTimer is started in a case that the HARQ RTT timer expires and data of an HARQ process is not successfully decoded, and the medium access control layer processing unit monitors the MPDCCH in an Active Time including a period in which the drx-InactivityTimer or the drx-RetransmissionTimer is running.

(2) According to a second aspect of the present invention, a communication method used for a terminal device, the communication method includes the steps of: monitoring an MPDCCH in a search space corresponding to a plurality of subframes; performing a DRX functionality for controlling monitoring of the MPDCCH; starting or restarting a drx-InactivityTimer in a next subframe of a last subframe in the search space in a case that the MPDCCH indicates initial transmission; starting an HARQ RTT timer in a case that the MPDCCH indicates downlink transmission; setting the HARQ RTT timer based on the number of times a PUCCH is repeatedly transmitted; starting a drx-RetransmissionTimer in a case that the HARQ RTT timer expires and data of an HARQ process is not successfully decoded; and monitoring the MPDCCH in an Active Time including a period in which the drx-InactivityTimer or the drx-RetransmissionTimer is running.

Effects of the Invention

According to the present invention, a terminal device and a base station device are capable of efficiently communicating using multiple physical channels included in multiple subframes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram of a radio communication system according to the present embodiment.

FIG. 2 is a diagram illustrating a schematic configuration of a radio frame according to the present embodiment.

FIG. 3 is a table illustrating one example of a UL-DL configuration in the present embodiment.

FIG. 4 is a diagram illustrating a configuration of a slot in present embodiment.

FIG. 5 is a diagram illustrating one example of narrow bands in the present embodiment.

FIG. 6 is a diagram illustrating one example of a search space in the present embodiment.

FIG. 7 is a diagram illustrating one example of a DRX cycle in the present embodiment.

FIG. 8 is a flowchart illustrating one example of a DRX operation in the present embodiment.

FIG. 9 is a flowchart illustrating the one example of the DRX operation in the present embodiment.

FIG. 10 is a diagram illustrating one example of monitoring PDCCH candidates in the present embodiment.

FIG. 11 is a diagram illustrating one example of transmission on a PUCCH in the present embodiment.

FIG. 12 is a diagram illustrating one example of a method for setting a drx-InactivityTimer and an HARQ RTT timer in the present embodiment.

FIG. 13 is a diagram illustrating another example of the method for setting the drx-InactivityTimer and the HARQ RTT timer in the present embodiment.

FIG. 14 is a schematic block diagram illustrating a configuration of a terminal device 1 in the present embodiment.

FIG. 15 is a schematic block diagram illustrating a configuration of a base station device 3 in the present embodiment.

MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below.

FIG. 1 is a conceptual diagram of a radio communication system according to the present embodiment. In FIG. 1, the radio communication system includes terminal devices 1A to 1C and a base station device 3. Each of the terminal devices 1A to 1C is referred to as a terminal device 1 below.

The present embodiment may be applied to an RRC_CONNECTED state, or only to the terminal device 1 in an RRC_CONNECTED mode. The present embodiment may be applied to an RRC_IDLE state or only to the terminal device 1 in the RRC_IDLE state. The present embodiment may be applied to both the RRC_CONNECTED state or the terminal device 1 in the RRC_CONNECTED mode, and the RRC_IDLE state or the terminal device 1 in the RRC_IDLE state.

In the present embodiment, one serving cell is configured for the terminal device 1. The one serving cell may be a primary cell. The one serving cell may be a cell on which the terminal device 1 is camping. The primary cell is a cell in which an initial connection establishment procedure has been performed, a cell in which a connection re-establishment procedure has started, or a cell indicated as a primary cell in a handover procedure.

A carrier corresponding to a serving cell in a downlink is referred to as a downlink component carrier. A carrier corresponding to a serving cell in an uplink is referred to as an uplink component carrier. The downlink component carrier and the uplink component carrier are collectively referred to as a component carrier. In FDD, the uplink component carrier and the downlink component carrier correspond to different carrier frequencies. In TDD, the uplink component carrier and the downlink component carrier correspond to the same carrier frequencies.

In the downlink, one independent HARQ entity exists for each serving cell (downlink component carrier). The HARQ entity manages multiple HARQ processes in parallel. Each of the HARQ processes instructs a physical layer to receive data based on a received downlink assignment (downlink control information).

In the downlink, at least one transport block is generated for each of one or more Transmission Time Intervals (TTIs) for each serving cell. The transport block and HARQ retransmission of the transport block are mapped to one serving cell. Note that, in LTE, a TTI serves as a subframe. The transport block in the downlink is MAC layer data transmitted on a DownLink Shared CHannel (DL-SCH).

In the present embodiment, in the uplink, “transport block”, “MAC Protocol Data Unit (PDU)”, “MAC layer data”, “DL-SCH”, “DL-SCH data”, and “downlink data” are assumed to mean the same thing.

Physical channels and physical signals according to the present embodiment will be described.

One physical channel is mapped to one or more subframes. In the present embodiment, “one physical channel included in multiple subframes”, “one physical channel mapped to multiple subframes”, “one physical channel including resources of multiple subframes”, and “one physical channel repeatedly transmitted over multiple subframes” are assumed to mean the same thing.

In uplink radio communication from the terminal device 1 to the base station device 3, the following uplink physical channels are used. The uplink physical channels are used for transmission of information output from higher layers.

-   -   Physical Uplink Control CHannel (PUCCH)     -   Physical Uplink Shared CHannel (PUSCH)     -   Physical Random Access CHannel (PRACH)

The PUCCH is used for transmission of Uplink Control Information (UCI). The uplink control information includes: downlink Channel State Information (CSI); a Scheduling Request (SR) to be used to request a PUSCH (UpLink-Shared CHannel (UL-SCH)) resource for initial transmission; and/or a Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) for downlink data (a Transport block, a Medium Access Control Protocol Data Unit (MAC PDU), a DownLink-Shared CHannel (DL-SCH), or a Physical Downlink Shared CHannel (PDSCH)). The HARQ-ACK indicates an acknowledgement (ACK) or a negative-acknowledgement (NACK). The HARQ-ACK is also referred to as ACK/NACK, HARQ feedback, an HARQ response, HARQ information, or HARQ control information.

The scheduling request includes a positive scheduling request or a negative scheduling request. The positive scheduling request indicates to request a UL-SCH resource for initial transmission. The negative scheduling request indicates not to request the UL-SCH resource for the initial transmission.

A PUCCH format 1 is used to transmit the positive scheduling request. A PUCCH format 1a is used to transmit 1-bit HARQ-ACK. In a case that the CSI and the HARQ-ACK are not multiplexed, a PUCCH format 2 may be used to report the CSI. The PUCCH format 2 may be used to report the CSI multiplexed with the HARQ-ACK with respect to an extended Cyclic Prefix (CP). A PUCCH format 2a may be used to report the CSI multiplexed with the HARQ-ACK with respect to a normal CP.

The PUSCH is used for transmission of uplink data (UpLink-Shared CHannel (UL-SCH)). Furthermore, the PUSCH may be used to transmit the HARQ-ACK and/or channel state information along with the uplink data. Furthermore, the PUSCH may be used to transmit only the channel state information. Furthermore, the PUSCH may be used to transmit only the HARQ-ACK and the channel state information.

Here, the base station device 3 and the terminal device 1 exchange (transmit and/or receive) signals with each other in their respective higher layers. For example, the base station device 3 and the terminal device 1 may transmit and/or receive RRC signaling in a Radio Resource Control (RRC) layer. The base station device 3 and the terminal device 1 may transmit and/or receive, in a Medium Access Control (MAC) layer, a MAC CE. Here, the RRC signaling and/or the MAC CE is also referred to as higher layer signaling. The RRC signaling and/or the MAC CE are/is included in a transport block.

In the present embodiment, “RRC signaling”, “RRC layer information”, “RRC layer signal” “RRC layer parameter”, “RRC message”, and “RRC information element” are assumed to mean the same thing.

The PUSCH is used to transmit the RRC signaling and the MAC CE. Here, the RRC signaling transmitted from the base station device 3 may be signaling common to multiple terminal devices 1 in a cell. The RRC signaling transmitted from the base station device 3 may be signaling dedicated to a certain terminal device 1 (also referred to as dedicated signaling). In other words, user device-specific (user device-unique) information is transmitted using the signaling dedicated to a certain terminal device 1.

The PRACH is used to transmit a random access preamble. The PRACH is used for indicating the initial connection establishment procedure, the handover procedure, the connection re-establishment procedure, synchronization (timing adjustment) for uplink transmission, and the request for the PUSCH (UL-SCH) resource.

The following uplink physical signal is used for uplink radio communication. The uplink physical signal is not used to transmit information output from the higher layer, but is used by a physical layer.

-   -   UpLink Reference Signal (UL RS)

The following downlink physical channels are used for downlink radio communication from the base station device 3 to the terminal device 1. The downlink physical channels are used for transmission of information output from higher layers.

-   -   Physical Broadcast CHannel (PBCH)     -   Physical Control Format Indicator CHannel (PCFICH)     -   Physical Hybrid automatic repeat request Indicator CHannel         (PHICH)     -   Physical Downlink Control CHannel (PDCCH)     -   Enhanced Physical Downlink Control CHannel (EPDCCH)     -   Machine type communication Physical Downlink Control Channel         (MPDCCH)     -   Physical Downlink Shared CHannel (PDSCH)     -   Physical Multicast CHannel (PMCH)

The PBCH is used for broadcasting a Master Information Block (MIB), or a Broadcast CHannel (BCH), that is shared by the terminal devices 1.

The PCFICH is used for transmission of information indicating a region (OFDM symbols) to be used for transmission of the PDCCH.

The PHICH is used for transmission of a HARQ indicator (HARQ feedback or response information) indicating an ACKnowledgement (ACK) or a Negative ACKnowledgement (NACK) for the uplink data (UpLink Shared CHannel (UL-SCH)) received by the base station device 3.

The PDCCH, the EPDCCH, and the MPDCCH are used for transmitting Downlink Control Information (DCI). In the present embodiment, the “PDCCH” is assumed to include the “EPDCCH” and the “MPDCCH”, for the sake of convenience. The downlink control information is also referred to as a DCI format. The downlink control information transmitted on one PDCCH includes a downlink grant and HARQ information, or an uplink grant and HARQ information. The downlink grant is also referred to as downlink assignment or downlink allocation. The downlink assignment and the uplink grant are not transmitted together on one PDCCH.

The downlink assignment is used for scheduling a single PDSCH within a single cell. The downlink assignment may be used for scheduling the PDSCH within the same subframe as the subframe in which the downlink grant is transmitted. The downlink assignment may be used for scheduling the PDSCH included in the subframe in which the downlink grant is transmitted and in one or more subsequent subframes.

The uplink grant is used for scheduling of a single PUSCH within a single cell. The uplink grant may be used for scheduling a PUSCH included in one or more subframes subsequent to the subframe in which the uplink grant is transmitted.

Cyclic Redundancy Check (CRC) parity bits attached to the downlink control information transmitted on one PDCCH are scrambled with a Cell-Radio Network Temporary Identifier (C-RNTI), a Semi Persistent Scheduling (SPS) C-RNTI, or a Temporary C-RNTI. The C-RNTI and the SPS C-RNTI are identifiers for identifying a terminal device within a cell. The Temporary C-RNTI serves as an identifier for identifying the terminal device 1 that has transmitted a random access preamble in a contention-based random access procedure.

The C-RNTI and the Temporary C-RNTI are used to control PDSCH transmission or PUSCH transmission in a single subframe. The SPS C-RNTI is used to periodically allocate a resource for the PDSCH or the PUSCH.

The PDSCH is used for transmission of downlink data (DownLink Shared CHannel (DL-SCH)).

The PMCH is used for transmission of multicast data (Multicast CHannel (MCH)).

The following downlink physical signals are used in the downlink radio communication. The downlink physical signals are not used to transmit the information output from the higher layer, but are used by the physical layer.

-   -   Synchronization Signal (SS)     -   DownLink Reference Signal (DL RS)

The synchronization signal is used for the terminal device 1 to be synchronized to frequency and time domains in the downlink. In the TDD scheme, the synchronization signal is mapped to subframes 0, 1, 5, and 6 within a radio frame. In the FDD scheme, the synchronization signal is mapped to subframes 0 and 5 within a radio frame.

The downlink reference signal is used for the terminal device 1 to perform channel compensation on a downlink physical channel. The downlink reference signal is used in order for the terminal device 1 to calculate the downlink channel state information.

According to the present embodiment, the following five types of downlink reference signals are used.

-   -   Cell-specific Reference Signal (CRS)     -   UE-specific Reference Signal (URS) associated with the PDSCH     -   Demodulation Reference Signal (DMRS) associated with the EPDCCH     -   Non-Zero Power Channel State Information-Reference Signal (NZP         CSI-RS)     -   Zero Power Channel State Information-Reference Signal (ZP         CSI-RS)     -   Multimedia Broadcast and Multicast Service over Single Frequency         Network Reference Signal (MBSFN RS)     -   Positioning Reference Signal (PRS)

The downlink physical channels and the downlink physical signals are collectively referred to as a downlink signal. The uplink physical channels and the uplink physical signals are collectively referred to as an uplink signal. The downlink physical channels and the uplink physical channels are collectively referred to as physical channels. The downlink physical signals and the uplink physical signals are collectively referred to as physical signals.

The BCH, the MCH, the UL-SCH, and the DL-SCH are transport channels. A channel used in the Medium Access Control (MAC) layer is referred to as a transport channel. The unit of the transport channel used in the MAC layer is also referred to as a Transport Block (TB) or a MAC Protocol Data Unit (PDU). A Hybrid Automatic Repeat reQuest (HARQ) is controlled for each transport block in the MAC layer. The transport block is a unit of data that the MAC layer delivers to the physical layer. In the physical layer, the transport block is mapped to a codeword and subjected to coding processing on a codeword-by-codeword basis.

A structure of a radio frame in the present embodiment will be described.

In LTE, two radio frame structures are supported. The two radio frame structures are Frame structure Type 1 and Frame structure Type 2. Frame structure Type 1 is applicable to FDD. Frame structure Type 2 is applicable to TDD.

FIG. 2 is a diagram illustrating a schematic configuration of the radio frame according to the present embodiment. In FIG. 2, the horizontal axis is a time axis. Each of radio frames of type 1 and type 2 is 10 ms in length, and is defined by 10 subframes. Each of the subframes is 1 ms in length and is defined by two consecutive slots. Each of the slots is 0.5 ms in length. The i-th subframe within a radio frame is constituted of the (2×i)-th slot and the (2×i+1)-th slot.

Following three types of subframes are defined for Frame structure Type 2.

-   -   Downlink subframe     -   Uplink subframe     -   Special subframe

The downlink subframe is a subframe reserved for the downlink transmission. The uplink subframe is a subframe reserved for the uplink transmission. The special subframe is constituted of three fields. The three fields are a Downlink Pilot Time Slot (DwPTS), a Guard Period (GP), and an Uplink Pilot Time Slot (UpPTS). The sum of lengths of the DwPTS, the GP, and the UpPTS is 1 ms. The DwPTS is a field reserved for the downlink transmission. The UpPTS is a field reserved for the uplink transmission. The GP is a field in which neither the downlink transmission nor the uplink transmission is performed. Moreover, the special subframe may be constituted of only the DwPTS and the GP, or may be constituted of only the GP and the UpPTS.

A radio frame of Frame structure Type 2 is constituted of at least the downlink subframe, the uplink subframe, and the special subframe. The constitution of the radio frame of Frame structure Type 2 is indicated by an uplink-downlink configuration (UL-DL configuration). The terminal device 1 receives information indicating the UL-DL configuration from the base station device 3. FIG. 3 is a table illustrating one example of the UL-DL configuration, in the present embodiment. In FIG. 3, D denotes a downlink subframe, U denotes an uplink subframe, and S denotes a special subframe.

A configuration of a slot in the present embodiment will be described below.

FIG. 4 is a diagram illustrating a configuration of a slot in the present embodiment. In the present embodiment, a normal Cyclic Prefix (CP) is applied to an OFDM symbol. Note that an extended Cyclic Prefix (CP) may be applied to the OFDM symbol. The physical signal or the physical channel transmitted in each of the slots is expressed by a resource grid. In FIG. 4, the horizontal axis represents a time axis, and the vertical axis represents a frequency axis. In downlink, the resource grid is defined by multiple subcarriers and multiple OFDM symbols. In uplink, the resource grid is defined by multiple subcarriers and multiple SC-FDMA symbols. The number of subcarriers constituting one slot depends on a cell bandwidth. The number of OFDM symbols or SC-FDMA symbols constituting one slot is seven. Each element within the resource grid is referred to as a resource element. The resource element is identified by a subcarrier number, and an OFDM symbol or an SC-FDMA symbol number.

A resource block is used to express mapping of a certain physical channel (such as the PDSCH or the PUSCH) to resource elements. For the resource block, a virtual resource block and a physical resource block are defined. A certain physical channel is first mapped to a virtual resource block. Thereafter, the virtual resource block is mapped to a physical resource block. One physical resource block is defined by seven consecutive OFDM symbols or SC-FDMA symbols in a time domain and by 12 consecutive subcarriers in a frequency domain. Hence, one physical resource block includes (7×12) resource elements. Furthermore, one physical resource block corresponds to one slot in the time domain and corresponds to 180 kHz in the frequency domain. Physical resource blocks are numbered from 0 in the frequency domain.

Hereinafter, narrow bands applicable to the present invention will be described.

FIG. 5 is a diagram illustrating one example of narrow bands in the present embodiment. In FIG. 5, the horizontal axis represents a time axis, and the vertical axis represents a frequency axis. In a slot, a narrow band is constituted of six consecutive physical resource blocks in the frequency domain. The terminal device 1 is not capable of performing simultaneous reception on multiple different narrow bands in one slot. The terminal device 1 may perform reception on a different narrow band for each of a slot, a subframe, and a subframe set. The terminal device 1 is not capable of performing simultaneous transmission on multiple different narrow bands in one slot. The terminal device 1 may perform transmission on a different narrow band for each of the slot, the subframe, and the subframe set.

The terminal device 1 needs a gap in the time domain to switch narrow bands in which the terminal device 1 performs reception processing. Moreover, the terminal device 1 also needs a gap in the time domain to switch narrow bands in which the terminal device 1 performs transmission processing. For example, in a case that the terminal device 1 performs reception processing in a first narrow band in a subframe n, the terminal device 1 may perform reception processing in a different narrow band from the first narrow band in a subframe n+2 without performing the reception processing in any narrow band in a subframe n+1. In other words, in a case that the terminal device 1 performs the reception processing in the first narrow band in the subframe n, the subframe n+1 may be the gap.

Hereinafter, a search space applicable to the present invention will be described. The search space is a set of PDCCH candidates. The PDCCH candidates include resources of one or more subframes.

The terminal device 1 monitors the set of PDCCH candidates in such one or more narrow bands configured by higher layer signaling, for downlink control information. Here, monitoring means an attempt to decode each of the PDCCHs in the set of PDCCH candidates in accordance with a format of the downlink control information to be monitored. In the present embodiment, monitoring of a set of PDCCH candidates is also simply referred to as monitoring PDCCHs.

In the present embodiment, “PDCCH candidate” and “MPDCCH candidate” are assumed to mean the same thing. In the present embodiment, “set of PDCCH candidates to be monitored”, “set of MPDCCH candidates to be monitored”, “search space”, “PDCCH search space”, “MPDCCH search space”, “UE-specific search space”, “PDCCH UE-specific search space”, and “MPDCCH UE-specific search space” are assumed to mean the same thing.

FIG. 6 is a diagram illustrating one example of a search space in the present embodiment.

In FIG. 6, one search space includes a PDCCH candidate 60 to a PDCCH candidate 69. The PDCCH candidate 60 to the PDCCH candidate 69 are included in an X-th narrow band. In FIG. 6, frequency hopping may be applied to the PDCCH candidates. For example, a narrow band including the PDCCH candidate 60 in a first subframe may be different from another narrow band including the PDCCH candidate 60 in a second subframe. To change a narrow band including a PDCCH candidate, a gap in the time domain (for example, a guard subframe) is needed.

In a slot, the number of resource blocks included in a PDCCH candidate is referred to as an Aggregation Level (AL) of the PDCCH candidate. The aggregation level of the PDCCH candidates 60, 61, 62, 66, and 68 is 2 (AL₀=2). The aggregation level of the PDCCH candidates 63, 64, 65, 67, and 69 is 4 (AL₁=4).

The number of subframes including one PDCCH candidate is referred to as a Repetition Level (RL) of the PDCCH candidate. The repetition level of the PDCCH candidates 60, 61, 62, 63, 64, and 65 is represented by RL₀. The repetition level of the PDCCH candidates 66 and 67 is represented by RL₁. The repetition level of the PDCCH candidates 68 and 69 is represented by RL₂.

Multiple PDCCH candidates included in the same search space may overlap each other. For example, in FIG. 6, the PDCCH candidate 68 overlaps the PDCCH candidates 60, 61, 62, and 66. The multiple subframes including the respective PDCCH candidates 60, 61, 62, and 66 are parts of the multiple subframes including the PDCCH candidate 68. In the frequency domain, two indices of the two resource blocks included in the PDCCH candidates 60, 61, 62, 66, and 68 are identical.

The position (subframes and resource blocks) of the search space in the time domain and/or in the frequency domain may be configured by a higher layer. The position (subframes and resource blocks) of the search space in the time domain and/or in the frequency domain may be configured by the terminal device 1, based on a higher layer message (an RRC message) received from the base station device 3.

The physical channel may not necessarily be included in a subframe satisfying a given condition. In the present embodiment, “multiple subframes including a physical channel” and “the number of subframes including a physical channel” may be defined in consideration of the subframe(s) satisfying the given condition, or may be defined without consideration of the subframe(s) satisfying the given condition.

The PDCCH candidates may not necessarily be included in a subframe satisfying the given condition. The repetition level of the PDCCH candidate may be defined without consideration of the subframe(s) satisfying the given condition. For example, in a case where a certain PDCCH candidate is included in a subframe 1 to a subframe 10 and two subframes included in the subframe 1 to the subframe 10 satisfy a given condition, the repetition level of the certain PDCCH candidate may be 10.

The repetition level of a PDCCH candidate may be defined in consideration of the subframe(s) satisfying the given condition. For example, in a case that a certain PDCCH candidate is included in the subframe 1 to the subframe 10 and two subframes included in the subframe 1 to the subframe 10 satisfy the given condition, the repetition level of the certain PDCCH candidate may be 8.

For example, the above-described given condition may include some or all of a condition (a) to a condition (d) below.

Condition (a): the subframe is reserved as an MBSFN subframe

Condition (b): in TDD, the subframe is an uplink subframe

Condition (c): the subframe is a gap (a guard subframe) for frequency hopping applied to the PDCCH candidate

Condition (d): the subframe is a part of a configured measurement gap

Note that the conditions included in the above-described given conditions are not necessarily limited to the condition (a) to the condition (d), may use one or more conditions different from the condition (a) to the condition (d), or may use some of the condition (a) to the condition (d).

In the present embodiment, “from the X-th subframe” includes the X-th subframe. In the present embodiment, “to the Y-th subframe” includes the Y-th subframe.

Now, Discontinuous Reception (DRX) applicable to the present invention will be described.

A DRX functionality is configured by a higher layer (RRC) and processed through MAC. The DRX functionality controls a PDCCH monitoring activity of the terminal device 1 for the C-RNTI and the SPS C-RNTI of the terminal device 1.

In other words, the DRX functionality controls the monitoring activity of the terminal device 1 for the PDCCH to be used to transmit a DCI format, to which the SPS C-RNTI of the terminal device 1 or CRC parity bits scrambled with the C-RNTI are attached.

With the configured DRX, the terminal device 1 may discontinuously monitor the PDCCHs through a DRX operation to be described below. In other cases, the terminal device 1 may continuously monitor PDCCHs.

The higher layer (RRC) controls the DRX operation by configuring the following multiple timers and a drxStartOffset value. Whether to configure a drxShortCycleTimer and a shortDRX-Cycle is optional for the higher layer (RRC).

-   -   onDurationTimer     -   drx-InactivityTimer     -   drx-RetransmissionTimer (one for each of downlink HARQ processes         except for a downlink HARQ process corresponding to a broadcast         process)     -   longDRX-Cycle     -   HARQ Round Trip Time (RTT) timer (one for each downlink HARQ         process)     -   drxShortCycleTimer (optional)     -   shortDRX-Cycle (optional)

The base station device 3 may transmit, to the terminal device 1, an RRC message including parameters/information indicating onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, longDRX-Cycle, drxShortCycleTimer, shortDRX-Cycle, and the value of drxStartOffset.

The terminal device 1 may set onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, longDRX-Cycle, drxShortCycleTimer, shortDRX-Cycle, and the value of drxStartOffset, based on the received RRC message.

longDRX-Cycle and shortDRX-Cycle are also collectively referred to as a DRX cycle.

onDurationTimer indicates the number of consecutive PDCCH subframes from the start of a DRX cycle.

drx-InactivityTimer indicates the number of consecutive PDCCH subframes subsequent to the subframe, to which the PDCCH indicating initial transmission of uplink data or downlink data to the terminal device 1 is mapped.

drx-RetransmissionTimer indicates the maximum number of consecutive PDCCH subframes for downlink retransmission expected by the terminal device 1. The same value of drx-RetransmissionTimer is applied to all serving cells.

The DRX cycle indicates an On Duration iteration cycle. An on-duration period is followed by a period in which a PDCCH monitoring inactivity of the terminal device 1 for a C-RNTI and an SPS C-RNTI of the terminal device 1 is enabled.

FIG. 7 is a diagram illustrating one example of the DRX cycle in the present embodiment. In FIG. 7, the horizontal axis represents a time axis. In FIG. 7, the terminal device 1 monitors PDCCHs in an on-duration period P2200. In FIG. 7, a period P2202 subsequent to the on-duration period P2200 is an inactivity-allowed period. In other words, in FIG. 7, the terminal device 1 may not monitor PDCCHs in the period P2202.

drxShortCycleTimer indicates the number of consecutive subframes in which the terminal device 1 follows a short DRX cycle.

drxStartOffset indicates a subframe in which the DRX cycle starts.

An HARQ RTT timer corresponding to a downlink HARQ process relates to the start of a drx-RetransmissionTimer and is managed for each downlink HARQ process. The HARQ RTT timer corresponding to a downlink HARQ process indicates the minimum interval from transmission of downlink data to retransmission of the downlink data. In other words, the HARQ RTT timer corresponding to the downlink HARQ process indicates the minimum number of subframes prior to downlink HARQ retransmission expected by the terminal device 1.

Note that, in the present embodiment, one downlink HARQ process controls the HARQ of one piece of downlink data (a transport block). Alternatively, one downlink HARQ process may control two pieces of downlink data.

For example, in a case that the DRX cycle is configured, an Active Time may include a period satisfying at least one of a condition (e) to a condition (i) below.

Condition (e): onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, or mac-ContentionResolutionTimer is running

Condition (f): a scheduling request is transmitted on a PUCCH and is pending

Condition (g): there is a possibility that an uplink grant for pending HARQ retransmission is transmitted for synchronous HARQ, and the corresponding HARQ buffer holds data

Condition (h): after successful reception of a random access response for a preamble that is not selected by the terminal device 1, a PDCCH, which is accompanied with the C-RNTI of the terminal device 1 and which indicates that initial transmission has not been received

Condition (i): the terminal device 1 is monitoring PDCCH candidates included in multiple subframes

Note that the conditions used to determine whether a certain period is included in an Active Time are not limited to the condition (e) to the condition (i), one or more conditions different from the condition (e) to the condition (i) may be used, or some of the condition (e) to the condition (i) may be used.

Once a timer starts, the timer keeps running until the timer is stopped or the timer expires. In other cases, the timer is not running. When the timer is not running, the timer has a possibility to be started. When the timer is running, the timer has a possibility to be restarted. The timer is always to be started or restarted from an initial value of the timer.

The preamble serves as a message 1 in a random access procedure, and is transmitted on a PRACH. The preamble that is not selected by the terminal device 1 relates to a contention-based random access procedure.

The random access response serves as a message 2 in the random access procedure, and is transmitted on a PDSCH. The base station device 3 transmits a random access response to the received preamble.

The terminal device 1 performing the contention-based random access procedure receives the random access response, and then transmits a message 3. After transmitting the message 3, the terminal device 1 monitors a PDCCH relating to a message 4.

mac-ContentionResolutionTimer indicates the number of consecutive subframes in which the terminal device 1 monitors the PDCCH after the transmission of the message 3.

FIG. 8 and FIG. 9 are flowcharts illustrating one example of a DRX operation in the present embodiment. In a case that the DRX is configured, the terminal device 1 performs the DRX operation for each of the subframes according to the flowcharts in FIG. 8 and FIG. 9.

If a HARQ RTT timer corresponding to the downlink HARQ process in the current subframe expires and the data of the HARQ process corresponding to the HARQ RTT timer is not decoded successfully (S800), the terminal device 1 starts a drx-RetransmissionTimer for the downlink HARQ process corresponding to the HARQ RTT timer (S802) and processing proceeds to S804. Otherwise (S800), processing of the terminal device 1 proceeds to S804.

If a DRX command MAC CE is received (S804), the terminal device 1 stops an onDurationTimer and a drx-InactivityTimer (S806), and processing proceeds to S808. Otherwise (S804), processing of the terminal device 1 proceeds to S808.

If the drx-InactivityTimer expires or a DRX command MAC CE is received in the current subframe (S808), processing of the terminal device 1 proceeds to S810. Otherwise (S808), processing of the terminal device 1 proceeds to S816.

If a short DRX-Cycle is not configured (S810), the terminal device 1 uses a long DRX cycle (S812), and processing proceeds to S816. If the short DRX-Cycle is configured (S810), the terminal device 1 starts or restarts a drxShortCycleTimer to use the short DRX-Cycle (S814) and processing proceeds to S816.

If the drxShortCycleTimer expires in the current subframe (S816), the terminal device 1 uses the long DRX cycle (S818) and processing proceeds to S900 in FIG. 9. Otherwise (S816), processing of the terminal device 1 proceeds to S900 in FIG. 9.

(1) If the short DRX-Cycle is used and [(SFN*10)+subframe number] modulo (shortDRX-Cycle)=(drxStartOffset) modulo (shortDRX-Cycle), or (2) if the long DRX-Cycle is used and [(SFN*10)+subframe number] modulo (longDRX-Cycle)=drxStartOffset (S900), the terminal device 1 starts an onDurationTimer (S902) and processing proceeds to S904. Otherwise (S900), processing of the terminal device 1 proceeds to S904.

If all conditions (j) to (n) below are satisfied (S904), the terminal device 1 monitors the PDCCH in the current subframe (906) and processing proceeds to S908.

Condition (j): the current subframe is included in an Active Time period

Condition (k): the current subframe is a PDCCH subframe

Condition (l): the current subframe is not necessary for uplink transmission to the terminal device 1 in a half-duplex FDD operation

Condition (m): the subframe is not a half-duplex guard subframe

Condition (n): the current subframe is not a part of a configured measurement gap

For one FDD serving cell, all subframes are PDCCH subframes. The terminal device 1 and the base station device 3 identify a PDCCH subframe for a TDD serving cell, based on the UL-DL configuration. The terminal device 1 for communicating with the base station device 3 through one TDD serving cell, and the base station device 3 identify (select or determine), as a PDCCH subframe, the subframe indicated as a downlink subframe or a subframe including DwPTS in the UL-DL configuration corresponding to the serving cell.

The half-duplex FDD operation includes a type A half-duplex FDD operation and a type B half-duplex FDD operation. The terminal device 1 may transmit information indicating whether to support the type A half-duplex FDD in the FDD band, to the base station device 3. The terminal device 1 may transmit information indicating whether to support the type B half-duplex FDD in the FDD band, to the base station device 3.

In the type A half-duplex FDD operation, the terminal device 1 is not capable of performing uplink transmission and downlink reception simultaneously.

In the type B half-duplex FDD operation, a subframe immediately before the subframe in which the terminal device 1 performs uplink transmission and a subframe immediately after the subframe in which the mobile station device 1 performs uplink transmission are each a half-duplex guard subframe.

In the type B half-duplex FDD operation, the terminal device 1 is not capable of performing uplink transmission and downlink reception simultaneously. In the type B half-duplex FDD operation, the terminal device 1 is not capable of performing downlink reception in a subframe immediately before the subframe in which the terminal device 1 performs uplink transmission. For the type B half-duplex FDD operation, the terminal device 1 is not capable of performing downlink reception in a subframe immediately after the subframe in which the terminal device 1 performs uplink transmission.

The measurement gap is a time interval for the terminal device 1 to perform measurements of cells operating on different frequencies and/or operating in different Radio Access Technologies (RATs). The base station device 3 transmits information indicating the period of the measurement gap to the terminal device 1. The terminal device 1 configures the period of the measurement gap, based on the information.

If at least one of the conditions (j) to (n) is not satisfied (S904), the terminal device 1 terminates the DRX operation for the current subframe. In other words, when at least one of the conditions (j) to (n) is not satisfied, the terminal device 1 need not monitor the PDCCH in the current subframe.

Note that the conditions used in S904 are not limited to the condition (j) to the condition (n). In S904, conditions different from the condition (j) to the condition (n) or some of the condition (j) to the condition (n) may be used.

If the downlink assignment received via the PDCCH indicates downlink transmission or if a downlink assignment is configured for the current subframe (S908), the terminal device 1 starts the HARQ RTT timer for the corresponding downlink HARQ process and stops a drx-RetransmissionTimer for the corresponding downlink HARQ process (S910). Otherwise (S908), processing of the terminal device 1 proceeds to S912.

The state in which a downlink assignment is configured denotes a state in which semi persistent scheduling is activated by the downlink assignment along with an SPS C-RNTI.

If the downlink assignment or the uplink grant received via the PDCCH indicates initial downlink or uplink transmission (S914), the terminal device 1 starts or restarts the drx-InactivityTimer (S914) and terminates the DRX operation for the current subframe. Otherwise (S912), the terminal device 1 terminates the DRX operation for the current subframe.

The terminal device 1 configured with DRX does not transmit any periodic SRS in a case of not in the Active Time.

FIG. 10 is a diagram illustrating one example of monitoring PDCCH candidates in the present embodiment.

In FIG. 10, a P100 indicates a period in which an onDurationTimer is running. Some of the multiple subframes including a PDCCH candidate 240 are not included in the Active Time, and the other subframes are included in the Active Time. A first subframe (T370) of the multiple subframes including the PDCCH candidate 240 is not included in the Active Time. The terminal device 1 may not necessarily monitor the PDCCH candidate 240, based on the fact that the first subframe (T370) of the multiple subframes including the PDCCH candidate 240 is not included in the Active Time.

All the multiple subframes including a PDCCH candidate 241 are included in the Active Time. A first subframe (T371) of the multiple subframes including the PDCCH candidate 241 is not included in the Active Time. The terminal device 1 may monitor the PDCCH candidate 241, based on the fact that the first subframe (T371) of the multiple subframes including the PDCCH candidate 241 is included in the Active Time.

A first subframe (T372) of the multiple subframes including a PDCCH candidate 242 is included in the Active Time. The terminal device 1 may monitor the PDCCH candidate 242, based on the fact that the first subframe (T372) of the multiple subframes including the PDCCH candidate 242 is included in the Active Time. Here, in a case where the subframe (T372) is included in the Active Time at the time of the subframe (T372), the Active Time may include multiple subframes including the PDCCH candidate 242.

The first subframe (T372) of the multiple subframes including the PDCCH candidate 242 is included in the Active Time. The terminal device 1 may monitor only a part, which is included in the Active Time, of the PDCCH candidate 242, based on the fact that the first subframe (T372) of the multiple subframes including the PDCCH candidate 242 is included in the Active Time. Here, the terminal device 1 may not monitor a part, which is not included in the Active Time, of the PDCCH candidate 242.

FIG. 11 is a diagram illustrating one example of PUCCH transmission in the present embodiment.

In FIG. 11, the P100 indicates a period in which the onDurationTimer is running. In FIG. 11, normally, a PUCCH 250 is repeatedly transmitted in a subframe n to a subframe n+Z. The PUCCH 250 is at least used for periodic CQI reporting. The terminal device 1 may receive information indicating the PUCCH resources to be used for the periodic CQI reporting, from the base station device 3. The information indicating the PUCCH resource to be used for the periodic CQI reporting may indicate at least the subframe to which the PUCCH to be used for the periodic CQI reporting is allocated. The PUCCH 250 is transmitted using the PUCCH format 2 or the PUCCH format 2a.

In (1) of FIG. 11, the PUCCH 250 includes the CQI, and does not include the HARQ-ACK. In (2) of FIG. 11, the PUCCH 250 includes the CQI and the HARQ-ACK.

In (1) and (2) of FIG. 11, the terminal device 1 transmits a scheduling request 251, and receives information 252, before a subframe n-X. The information 252 may include a downlink assignment, an uplink grant, and a DRX command MAC CE.

The terminal device 1 may receive, from the base station device 3, information (an RRC message) indicating that the terminal device 1 performs setup or release of a higher layer parameter/CQI-masking (cqi-Mask).

In a case where the higher layer parameter/CQI-masking (cqi-Mask) is not configured by a higher layer and a subframe n is not included in the Active Time in consideration of the scheduling request 251 which has been transmitted and/or the information 252 which has been received before a subframe n-X, the terminal device 1 may not report the CQI using the PUCCH 250 included in the subframe n to the subframe n+Z, irrespective of whether the subframe n+1 to the subframe n+Z are included in the Active Time.

The value of X may be defined beforehand in a specification, for example. For example, X is 5. The terminal device 1 may receive information relating to the value of Z, from the base station device 3. The value of Z relates to the PUCCH 250 or the number of times the uplink control information is repeatedly transmitted. In other words, the PUCCH 250 and the uplink control information are repeatedly transmitted (Z+1) times.

In a case where the higher layer parameter/CQI-masking (cqi-Mask) is not configured by a higher layer and the subframe n is included in the Active Time in consideration of the scheduling request 251 which has been transmitted and/or the information 252 which has been received before the subframe n-X, the terminal device 1 starts to report the CQI using the PUCCH 250 in the subframe n. Here, in a case that the PUCCH 250 does not include the HARQ-ACK and the higher layer parameter/CQI masking (cqi-Mask) is not configured by the higher layer, the terminal device 1 may not report the CQI in a subframe which is not included in the Active Time (from the subframe n+Y to the subframe n+Z) among the subframes from the subframe n to the subframe n+Z ((1) of FIG. 11). Here, in a case that the PUCCH 250 includes the HARQ-ACK and the higher layer parameter/CQI masking (cqi-Mask) is not configured by the higher layer, the terminal device 1 may report the CQI using the PUCCH 250 in the subframe which is not included in the Active Time (from the subframe n+Y to the subframe n+Z) among the subframes from the subframe n to the subframe n+Z ((2) of FIG. 11).

In a case where the higher layer parameter/CQI-masking (cqi-Mask) is configured by a higher layer and the onDurationTimer is not running in the subframe n in consideration of the scheduling request 251 which has been transmitted and/or the information 252 which has been received before the subframe n-X, the terminal device 1 may not report the CQI using the PUCCH 250 included in the subframe n to the subframe n+Z irrespective of whether the onDurationTimer is running in the subframe n+1 to the subframe n+Z.

In a case where the higher layer parameter/CQI-masking (cqi-Mask) is configured by a higher layer and the onDurationTimer is running in the subframe n in consideration of the scheduling request 251 which has been transmitted and/or the information 252 which has been received before the subframe n-X, the terminal device 1 starts to report the CQI using the PUCCH 250 in the subframe n. Here, in a case that the PUCCH 250 does not include the HARQ-ACK and the higher layer parameter/CQI masking (cqi-Mask) is configured by the higher layer, the terminal device 1 may not report the CQI in a subframe in which the onDurationTimer is not running (from the subframe n+Y to the subframe n+Z) among the subframes from the subframe n to the subframe n+Z ((1) of FIG. 11). Here, in a case that the PUCCH 250 includes the HARQ-ACK and the higher layer parameter/CQI masking (cqi-Mask) is configured by the higher layer, the terminal device 1 may report the CQI using the PUCCH 250 in the subframe in which the onDurationTimer is not running (from the subframe n+Y to the subframe n+Z) among the subframes from the subframe n to the subframe n+Z ((2) of FIG. 11).

In other words, irrespective of (i) whether the terminal device 1 monitors the PDCCH, (ii) the Active Time, and (iii) the onDurationTimer, in a case that transmission of a bundle to the repeatedly transmitted PUCCH is once started, the PUCCH format and the PUCCH contents with respect to the PUCCH transmission do not change in the bundle.

The terminal device 1 may apply any one of the above-described examples to CQI reporting on the PUCCH 250 irrespective of whether the higher layer parameter/CQI-masking (cqi-Mask) is configured by a higher layer.

The terminal device 1 transmits a HARQ-ACK on the PUCCH included in a subframe m to a subframe m+Z irrespective of whether some or all of the subframe m to the subframe m+Z are included in the Active Time and whether the onDurationTimer is running in some or all of the subframe m to the subframe m+Z.

Hereinafter, a method for setting a drx-InactivityTimer and a HARQ RTT timer in the present embodiment will be described in detail.

FIG. 12 is a diagram illustrating one example of a method for setting the drx-InactivityTimer and the HARQ RTT timer in the present embodiment. FIG. 13 is a diagram illustrating another example of the method for setting a drx-InactivityTimer and a HARQ RTT timer in the present embodiment. Note that the example in FIG. 12 and the example in FIG. 13 may be applied to only one of the drx-InactivityTimer and the HARQ RTT timer. Alternatively, different examples may be applied to the drx-InactivityTimer and the HARQ RTT timer.

In FIG. 12 and FIG. 13, the P100 indicates a period while an onDurationTimer is running, a P110 indicates a period while a drx-InactivityTimer is running, a P120 indicates a period while the HARQ RTT timer is running, and a P130 indicates a period while the drx-RetransmissionTimer is running. A PDCCH candidate 200 is included in a first subframe (a time point T300) to a second subframe (a time point T310), and a PDCCH candidate 210 is included in the first subframe (the time point T300) to the second subframe (a time point T320). The terminal device 1 monitors a search space 240 including the PDCCH candidate 200 and the PDCCH candidate 210. Other PDCCH candidates different from the PDCCH candidates 200 and 210 may be included in the search space 240. Note that the PDCCH candidate 210 has the highest repetition level among the multiple PDCCH candidates included in the search space 240.

The terminal device 1 detects a PDCCH 220 from the first subframe (the time point T300) to the second subframe (the time point T310). In FIG. 12 and FIG. 13, the terminal device 1 decodes a PDSCH 230 included in a fourth subframe (a time point T330) to a fifth subframe (a time point T340), based on the detection of the PDCCH 220. The multiple subframes (the fourth subframe and/or the fifth subframe) including the PDSCH 230 may be given by the information included in the PDCCH 220 and/or in the higher layer parameter (an RRC message). The number of subframes including the PDSCH 230 may be given by the information included in the PDCCH 220 and/or in the higher layer parameter (the RRC message).

The terminal device 1 transmits, based on detection of the PDSCH 230, the HARQ-ACK corresponding to the PDSCH 230 using the PUCCH 250. The transmission of the PUCCH 250 does not depend on the Active Time. The number of subframes including the PUCCH 250 may be given by the information included in the PDCCH 220 and/or in the higher layer parameter (the RRC message).

In FIG. 12, in the last subframe of the subframes including the detected PDCCH 220 or the next subframe of the last subframe, the terminal device 1 (i) sets the drx-InactivityTimer at the sum of A and B, (ii) starts the drx-InactivityTimer, (iii) sets the HARQ RTT timer at the sum of A, C, D, and E, and (iv) starts the HARQ RTT timer.

In FIG. 13, in the last subframe of the subframes including the PDCCH candidate 210 having the highest repetition level among the multiple PDCCH candidates included in the search space 240, in which the PDCCH 220 has been detected, or in the next subframe of the last subframe, the terminal device 1 (i) sets the drx-InactivityTimer at B, (ii) starts the drx-InactivityTimer, (iii) sets the HARQ RTT timer at the sum of C, D, and E, and (iv) starts the HARQ RTT timer.

In FIG. 12 and FIG. 13, when the terminal device 1 detects a PDCCH in the PDCCH candidate 210, the terminal device 1 (i) sets the drx-InactivityTimer at B, (ii) starts the drx-InactivityTimer, (iii) sets the HARQ RTT timer at the sum of C, D, and E, and (iv) starts the HARQ RTT timer, in the last subframe of the subframes including the PDCCH candidate 210 or in the next subframe of the last subframe.

The value of A is given by (i) the difference between the number of subframes including the detected PDCCH 220 and the number of subframes including the PDCCH candidate 210, (ii) the difference between the number of subframes including the PDCCH candidates 200, in which the PDCCH 220 is detected, and the number of subframes including the PDCCH candidate 210, (iii) the difference between the repetition level of the PDCCH candidate 200 and the repetition level of the PDCCH candidate 210, or (iv) the difference between the last subframe including the detected PDCCH 220 and the last subframe including the PDCCH candidate 210.

The value of B is given by a higher layer. The value of B is given by a higher layer parameter. The terminal device 1 may receive the higher layer parameter used to indicate the value of B, from the base station device 3.

The value of C may be defined beforehand in a specification, for example. For example, C is 0 or 1. The value of C may be given by the UL-DL configuration. The value of C may be given by the information included in the detected PDCCH 220 and/or a higher layer parameter.

The value of D is the number of subframes including the PDSCH 230. In other words, the value of D may be given by the information included in the PDCCH 220 and/or a higher layer parameter (an RRC message). The information on the value of D, of the information included in the PDCCH 220, may be the same as or different from the information on the value of C.

The value of E is given by a higher layer. The value of E is given by the information included in the PDCCH 220 and/or a higher layer parameter. The terminal device 1 may receive the higher layer parameter used to indicate the value of E, from the base station device 3. The value of E may be given by the number of times the PUCCH 250 is repeatedly transmitted.

In a case where the PDCCH candidate 200 and the PDCCH candidate 210 overlap each other and the base station device 3 transmits the PDCCH candidate 210 on the PDCCH candidate 220, the terminal device 1 is capable of detecting the PDCCH 220 in both the PDCCH candidate 200 and the PDCCH candidate 210. In this case, the terminal device 1 is not capable of identifying which one of the PDCCH candidate 200 and the PDCCH candidate 210 has transmitted the detected PDCCH 220.

However, in the example in FIG. 12 and in the example in FIG. 13, in a case that the terminal device 1 detects the PDCCH 220 in the PDCCH candidate 200, and also in a case that the terminal device 1 detects the PDCCH 220 in the PDCCH candidate 210, the drx-InactivityTimer expires in an identical subframe (a time point T350), and the HARQ RTT timer expires in an identical subframe (a time point T360). Hence, even in a case where the terminal device 1 fails to identify which one of the PDCCH candidate 200 and the PDCCH candidate 210 has transmitted the detected PDCCH 220 by using the method in the example in FIG. 12 and the example in FIG. 13, the base station device 3 is capable of learning the state of the drx-InactivityTimer and/or the HARQ RTT timer in the terminal device 1 with accuracy, by the terminal device 1 using the example in FIG. 12 or the example in FIG. 13 and by the base station device 3 assuming that the terminal device 1 is using the example in FIG. 12 or the example in FIG. 13. With this configuration, the base station device 3 is capable of efficiently controlling the DRX of the terminal device 1, and the terminal device 1 and the base station device 3 are capable of communicating efficiently.

Structures of devices according to the present embodiment will be described below.

FIG. 14 is a schematic block diagram illustrating a configuration of the terminal device 1 in the present embodiment. As illustrated, the terminal device 1 includes a radio transmission and/or reception unit 10 and a higher layer processing unit 14. The radio transmission and/or reception unit 10 includes an antenna unit 11, a Radio Frequency (RF) unit 12, and a baseband unit 13. The higher layer processing unit 14 includes a medium access control layer processing unit 15 and a radio resource control layer processing unit 16. The radio transmission and/or reception unit 10 is also referred to as a transmission unit, a reception unit, a measurement unit, or a physical layer processing unit.

The higher layer processing unit 14 outputs uplink data (transport block) generated by a user operation or the like, to the radio transmission and/or reception unit 10. The higher layer processing unit 14 performs processing of the Medium Access Control (MAC) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, and the Radio Resource Control (RRC) layer.

The medium access control layer processing unit 15 included in the higher layer processing unit 14 performs processing of a medium access control layer. The medium access control layer processing unit 15 controls HARQ in accordance with the various pieces of configuration information/parameters managed by the radio resource control layer processing unit 16. The medium access control layer processing unit 15 manages multiple HARQ entities, multiple HARQ processes, and multiple HARQ buffers.

The medium access control layer processing unit 15 identifies (selects, determines) a PDCCH subframe. The medium access control layer processing unit 15 performs processing of DRX, based on the PDCCH subframe. The medium access control layer processing unit 15 manages a timer relating to DRX, based on the PDCCH subframe. The medium access control layer processing unit 15 instructs the radio transmission and/or reception unit 10 to monitor the PDCCH in the subframe. The monitoring of the PDCCH denotes an attempt to decode the PDCCH in accordance with a DCI format.

The radio resource control layer processing unit 16 included in the higher layer processing unit 14 performs processing of a radio resource control layer. The radio resource control layer processing unit 16 manages the various configuration information/parameters of the terminal device 1 itself. The radio resource control layer processing unit 16 sets the various pieces of configuration information/parameters in accordance with RRC layer signaling received from the base station device 3. Specifically, the radio resource control layer processing unit 16 sets the various configuration information/parameters in accordance with the information indicating the various configuration information/parameters received from the base station device 3.

The radio transmission and/or reception unit 10 performs processing of the physical layer, such as modulation, demodulation, coding, and decoding. The radio transmission and/or reception unit 10 demultiplexes, demodulates, and decodes a signal received from the base station device 3, and outputs the information resulting from the decoding to the higher layer processing unit 14. The radio transmission and/or reception unit 10 modulates and codes data to generate a transmit signal, and transmits the transmit signal to the base station device 3.

The RF unit 12 converts (down-converts) a signal received through the antenna unit 11 into a baseband signal by orthogonal demodulation and removes unnecessary frequency components. The RF unit 12 outputs the processed analog signal to the baseband unit.

The baseband unit 13 converts the analog signal input from the RF unit 12 into a digital signal. The baseband unit 13 removes a portion corresponding to a Cyclic Prefix (CP) from the digital signal resulting from the conversion, performs Fast Fourier Transform (FFT) on the signal from which the CP has been removed, and extracts a signal in the frequency domain.

The baseband unit 13 performs Inverse Fast Fourier Transform (IFFT) on data, generates an SC-FDMA symbol, attaches a CP to the generated SC-FDMA symbol, generates a baseband digital signal, and converts the baseband digital signal into an analog signal. The baseband unit 13 outputs the analog signal resulting from the conversion, to the RF unit 12.

The RF unit 12 removes unnecessary frequency components from the analog signal input from the baseband unit 13 using a low-pass filter, up-converts the analog signal into a signal of a carrier frequency, and transmits the final result via the antenna unit 11. Furthermore, the RF unit 12 amplifies power. Furthermore, the RF unit 12 may have a function of controlling transmit power. The RF unit 12 is also referred to as a “transmit power control unit”.

FIG. 15 is a schematic block diagram illustrating a configuration of the base station device 3 in the present embodiment. As illustrated, the base station device 3 includes a radio transmission and/or reception unit 30 and a higher layer processing unit 34. The radio transmission and/or reception unit 30 includes an antenna unit 31, an RF unit 32, and a baseband unit 33. The higher layer processing unit 34 includes a medium access control layer processing unit 35 and a radio resource control layer processing unit 36. The radio transmission and/or reception unit 30 is also referred to as a transmission unit, a reception unit or a physical layer processing unit.

The higher layer processing unit 34 performs processing of the Medium Access Control (MAC) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, and the Radio Resource Control (RRC) layer.

The medium access control layer processing unit 35 included in the higher layer processing unit 34 performs processing of the medium access control layer. The medium access control layer processing unit 15 controls HARQ in accordance with the various pieces of configuration information/parameters managed by the radio resource control layer processing unit 16. The medium access control layer processing unit 15 generates an ACK/NACK and HARQ information with respect to uplink data (UL-SCH). The ACK/NACK and HARQ information with respect to the uplink data (UL-SCH) are transmitted to the terminal device 1 on the PHICH or the PDCCH.

The radio resource control layer processing unit 36 included in the higher layer processing unit 34 processes the radio resource control layer. The radio resource control layer processing unit 36 generates, or acquires from a higher node, downlink data (transport block) arranged on a physical downlink shared channel, system information, an RRC message, a MAC Control Element (CE), and the like, and outputs the generated or acquired data to the radio transmission and/or reception unit 30. Furthermore, the radio resource control layer processing unit 36 manages various configuration information/parameters for each of the terminal devices 1. The radio resource control layer processing unit 36 may set various configuration information/parameters for each of the terminal devices 1 via the higher layer signaling. In other words, the radio resource control layer processing unit 36 transmits/broadcasts information indicating various configuration information/parameters.

The functionality of the radio transmission and/or reception unit 30 is similar to that of the radio transmission and/or reception unit 10, and hence description thereof is omitted.

Each of the units in FIG. 14 and FIG. 15 may be constituted as a circuit. For example, the medium access control layer processing unit may be constituted as a medium access control layer processing unit circuit.

Hereinafter, various aspects of the terminal device and the base station device in the present embodiment will be described.

(1) In a first aspect of the present embodiment, a terminal device 1 includes a reception unit 10 configured to attempt to decode each of multiple Physical Downlink Control CHannels (PDCCHs) in a set of multiple PDCCH candidates in an Active Time, in a case where discontinuous reception is configured. The Active Time includes a period while a first timer (a drx-InactivityTimer) is running. The multiple PDCCH candidates include one or more first PDCCH candidates and one or more second PDCCH candidates. Each of the one or more first PDCCH candidates is included in a first subframe to a second subframe. Each of the one or more second PDCCH candidates is included in the first subframe to a third subframe subsequent to the second subframe. In a case that the PDCCH is detected in one of the one or more first PDCCH candidates, the first timer is set based on at least a first higher layer parameter value and a first value, and the first timer is started in the second subframe. Here, the first value is based on at least the number of subframes including the first PDCCH candidate and the number of subframes including the second PDCCH candidate.

(2) In the first aspect of the present embodiment, the reception unit 10 receives a first subframe number or information indicating a position of the first subframe.

(3) In a second aspect of the present embodiment, a terminal device 1 includes a reception unit 10 configured to attempt to decode each of multiple Physical Downlink Control CHannels (PDCCHs) in a set of multiple PDCCH candidates in an Active Time, in a case where discontinuous reception is configured. The Active Time includes a period while a first timer (a drx-InactivityTimer) is running. The multiple PDCCH candidates include one or more first PDCCH candidates and one or more second PDCCH candidates. Each of the one or more first PDCCH candidates is included in multiple subframes from a first subframe to a second subframe. Each of the one or more second PDCCH candidates is included in multiple subframes from the first subframe to a third subframe subsequent to the second subframe. In a case that the PDCCH is detected in one of the one or more first PDCCH candidates, the first timer is set, based on at least a first higher layer parameter value, and the first timer is started in the third subframe.

(4) In the second aspect of the present embodiment, the reception unit 10 the reception unit 10 receives the number of the first subframe or information indicating the position of the first subframe.

(5) In a third aspect of the present embodiment, a terminal device 1 includes a reception unit 10 configured to attempt to decode each of multiple Physical Downlink Control CHannels (PDCCHs) in a set of multiple PDCCH candidates in an Active Time, in a case where discontinuous reception is configured. The Active Time includes a period in which a first timer (a drx-RetransmissionTimer) is running. The first timer is started on the expiration of a second timer (a HARQ RTT timer). The multiple PDCCH candidates include one or more first PDCCH candidates and one or more second PDCCH candidates. Each of the one or more first PDCCH candidates is included in multiple subframes from a first subframe to a second subframe. Each of the one or more second PDCCH candidates is included in multiple subframes from the first subframe to a third subframe subsequent to the second subframe. In a case that the PDCCH is detected in one of the one or more first PDCCH candidates, the second timer is set based on at least a first higher layer parameter value, a first value, and a second value, and the second timer is started in the second subframe. The first value is based on at least the number of subframes including the first PDCCH candidate and the number of subframes including the second PDCCH candidate. The second value is based on at least (I) information included in the detected PDCCH in the first PDCCH candidates and/or (II) the number of subframes including the first PDCCH candidates.

(6) In the third aspect of the present embodiment, the reception unit 10 receives a first subframe number or information indicating a position of the first subframe.

(7) In a fourth aspect of the present embodiment, a terminal device 1 includes a reception unit 10 configured to attempt to decode each of multiple Physical Downlink Control CHannels (PDCCHs) in a set of multiple PDCCH candidates in an Active Time, in a case where discontinuous reception is configured. The Active Time includes a period while a first timer (a drx-RetransmissionTimer) is running. The first timer is started on the expiration of a second timer (a HARQ RTT timer). The multiple PDCCH candidates include one or more first PDCCH candidates and one or more second PDCCH candidates. Each of the one or more first PDCCH candidates is included in multiple subframes from a first subframe to a second subframe. Each of the one or more second PDCCH candidates is included in multiple subframes from the first subframe to a third subframe subsequent to the second subframe. In a case that the PDCCH is detected in one of the one or more first PDCCH candidates, the second timer (a HARQ RTT timer) is set based on at least a first higher layer parameter value and a first value, and the second timer is started in the third subframe. The first value is based on at least (I) information included in the detected PDCCH in the first PDCCH candidates and/or (II) the number of subframes including the first PDCCH candidates.

(8) In the fourth aspect of the present embodiment, the reception unit 10 receives a first subframe number or information indicating a position of the first subframe.

(9) In a fifth aspect of the present embodiment, a terminal device 1 includes a reception unit 10 configured to attempt to decode each of multiple Physical Downlink Control CHannels (PDCCHs) in a set of multiple PDCCH candidates in an Active Time, in a case where discontinuous reception is configured. The multiple PDCCH candidates include one or more first PDCCH candidates. Each of the one or more first PDCCH candidates is included in a first subframe to a second subframe. Irrespective of whether the subframes from the next subframe of the first subframe to the second subframe are included in the Active Time, the reception unit 10 does not attempt to decode each of the multiple PDCCHs of the one or more first PDCCH candidates, in a case that the first subframe is not included in the Active Time.

(10) In the fifth aspect of the present embodiment, the multiple PDCCH candidates include one or more second PDCCH candidates. Each of the one or more second PDCCH candidates is included in multiple subframes from a third subframe to a fourth subframe. Irrespective of whether the subframes from the next subframe of the third subframe to the fourth subframe are included in the Active Time, the reception unit 10 attempts to decode each of the multiple PDCCHs among the one or more second PDCCH candidates in a case that the third subframe is included in the Active Time.

(11) In a sixth aspect of the present embodiment, a reception unit 10 configured to attempt to decode each of multiple Physical Downlink Control CHannels (PDCCHs) in a set of multiple PDCCH candidates in an Active Time, in a case where discontinuous reception is configured; and a transmission unit 10 configured to report a Channel Quality Indicator (CQI) on a first Physical Uplink Control CHannel (PUCCH) included in a first subframe to a second subframe are included. In a case where a first higher layer parameter/CQI masking (cqi-Mask) is not configured by a higher layer and the first subframe is not included in the Active Time in consideration of information (a downlink assignment, an uplink grant, and/or a DRX command MAC CE) received and/or a scheduling request transmitted before a subframe earlier than the first subframe by X subframes, the transmission unit 10 does not report the CQI on the PUCCH included in the first subframe to the second subframe, irrespective of whether the next subframe of the first subframe to the second subframe are included in the Active Time.

(12) In the sixth aspect of the present embodiment, in a case where the first higher layer parameter is configured by a higher layer and a first timer (an onDurationTimer) is not running in the first subframe in consideration of information received and/or a scheduling request transmitted before the first subframe, the transmission unit 10 does not report the CQI on the PUCCH included in the first subframe to the second subframe, irrespective of whether the first timer (the onDurationTimer) is running in a next subframe of the first subframe to the second subframe.

(13) In the sixth aspect of the present embodiment, a second PUCCH for reporting of the CQI is included in a third subframe to a fourth subframe. In a case where the first higher layer parameter is not configured by a higher layer and the third subframe is included in the Active Time in consideration of information received and/or a scheduling request transmitted before the third subframe, the transmission unit 10 reports the CQI on the second PUCCH included in the third subframe to the fourth subframe, irrespective of whether a next subframe of the third subframe to the fourth subframe are included in the Active Time.

(14) In the sixth aspect of the present embodiment, in a case where the first higher layer parameter is configured by a higher layer and a first timer (an onDurationTimer) is running in the third subframe in consideration of information received and/or a scheduling request transmitted before the third subframe, the transmission unit 10 reports the CQI on the second PUCCH included in the third subframe to the fourth subframe, irrespective of whether the first timer (the onDurationTimer) is running in the subframes from the next subframe of the third subframe to the fourth subframe.

(15) In the sixth aspect of the present embodiment, a third PUCCH for transmission of a Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) is included in a fifth subframe to a sixth subframe. The transmission unit 10 transmits the HARQ-ACK on the third PUCCH included in the fifth subframe to the sixth subframe, irrespective of whether some of or all of the fifth subframe to the sixth subframe are included in the Active Time.

(16) In the sixth aspect of the present embodiment, the above-described X is 5.

(17) In a seventh aspect of the present embodiment, the terminal device 1 includes a measurement unit 30 configured to calculate one Channel Quality Indicator (CQI), and a transmission unit 30 configured to repeatedly transmit uplink control information including at least the one CQI using each of multiple Physical Uplink Control CHannels (PUCCHs) in multiple subframes. In a case that the uplink control information is transmitted in the PUCCH in the initial subframe included in the multiple subframes, based on whether the uplink control information includes a Hybrid Automatic Repeat Request-Acknowledgement (HARQ-ACK), (i) the uplink control information is transmitted using the PUCCH in a first subframe, or (ii) the uplink control information is not transmitted in the first subframe, the first subframe is included in the multiple subframes, and the subframe different from the initial subframe.

(18) In the seventh aspect of the present embodiment, the terminal device 1 includes a reception unit configured to attempt to decode each of multiple Physical Downlink Control CHannels (PDCCHs) in a set of multiple PDCCH candidates in an Active Time in a case that discontinuous reception (DRX) is configured. In a case that the uplink control information does not include the HARQ-ACK and in a case that a first higher layer parameter/CQI masking (cqi-Mask) is not configured, whether the uplink control information is transmitted in the first subframe is based on whether the first subframe is included in the Active Time. In a case that the uplink control information does not include the HARQ-ACK and in a case where the first higher layer parameter/CQI masking (cqi-Mask) is configured, whether the uplink control information is transmitted in the first subframe is based on whether a first timer (onDurationTimer) is running in the first subframe. In a case where the Active Time includes a period in which the first timer (onDurationTimer) is running and in a case where the uplink control information includes the HARQ-ACK, whether the uplink control information is transmitted in the first subframe is not based on whether the first subframe is included in the Active Time and whether the first timer (onDurationTimer) is running in the first subframe.

(19) In the seventh aspect of the present embodiment, in a case that the first higher layer parameter/CQI masking (cqi-Mask) is not configured, whether the uplink control information is transmitted in the initial subframe is based on whether the initial subframe is included in the Active Time, in a case that the first higher layer parameter/CQI masking (cqi-Mask) is configured, whether the uplink control information is transmitted in the initial subframe is based on whether the first timer (onDurationTimer) is running in the initial subframe.

(20) In the seventh aspect of the present embodiment, whether the subframe included in the multiple subframes is included in the Active Time, and whether the first timer (onDurationTimer) is running in the subframe included in the multiple subframes are based on received information and/or a transmitted scheduling request before a subframe earlier than the subframe included in the multiple subframes by X subframes.

(21) In the seventh aspect of the present embodiment, the above-described X is 5.

With this configuration, the terminal device 1 is capable of efficiently communicating with the base station device 3.

A program running on each of the base station device 3 and the terminal device 1 according to the present invention may serve as a program that controls a Central Processing Unit (CPU) and the like (a program for causing a computer to operate) in such a manner as to enable the functionalities according to the above-described embodiment of the present invention. The information handled in these devices is temporarily stored in a Random Access Memory (RAM) while being processed. Thereafter, the information is stored in various types of Read Only Memory (ROM) such as a flash ROM and a Hard Disk Drive (HDD), and when necessary, is read by the CPU to be modified or rewritten.

Moreover, the terminal device 1 and the base station device 3 according to the above-described embodiment may be partially achieved by a computer. In this case, this configuration may be realized by recording a program for realizing such control functions on a computer-readable recording medium and causing a computer system to read the program recorded on the recording medium for execution.

Note that it is assumed that the “computer system” refers to a computer system built into the terminal device 1 or the base station device 3, and the computer system includes an OS and hardware components such as a peripheral device. Furthermore, the “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, and a CD-ROM, and a storage device such as a hard disk built into the computer system.

Moreover, the “computer-readable recording medium” may include a medium that dynamically retains the program for a short period of time, such as a communication line that is used to transmit the program over a network such as the Internet or over a communication line such as a telephone line, and a medium that retains, in that case, the program for a fixed period of time, such as a volatile memory within the computer system which functions as a server or a client. Furthermore, the program may be configured to realize some of the functions described above, and also may be configured to be capable of realizing the functions described above in combination with a program already recorded in the computer system.

Furthermore, the base station device 3 according to the above-described embodiment is achieved as an aggregation (a device group) constituted of multiple devices. Devices constituting such a device group may be each equipped with some or all portions of each function or each functional block of the base station device 3 according to the above-described embodiment. The device group may include at least general functionalities or general functional blocks of the base station device 3. Furthermore, the terminal device 1 according to the above-described embodiments can also communicate with the base station device as the aggregation.

Furthermore, the base station device 3 according to the above-described embodiment may serve as an Evolved Universal Terrestrial Radio Access Network (EUTRAN). Furthermore, the base station device 3 according to the above-described embodiment may have some or all portions of the functionalities of a node higher than an eNodeB.

Furthermore, some or all portions of each of the terminal device 1 and the base station device 3 according to the above-described embodiment may be achieved as an LSI which is a typical integrated circuit or may be achieved as a chip set. The functional blocks of each of the terminal device 1 and the base station device 3 may be individually achieved as a chip, or some or all of the functional blocks may be integrated into a chip. Furthermore, a circuit integration technique is not limited to the LSI, and may be realized with a dedicated circuit or a general-purpose processor. Furthermore, in a case where with advances in semiconductor technology, a circuit integration technology with which an LSI is replaced appears, it is also possible to use an integrated circuit based on the technology.

Furthermore, according to the above-described embodiment, the terminal device has been described as an example of a communication device, but the present invention is not limited to such a terminal device, and is applicable to a terminal device or a communication device of a fixed-type or a stationary-type electronic apparatus installed indoors or outdoors, for example, such as an Audio-Video (AV) apparatus, a kitchen apparatus, a cleaning or washing machine, an air-conditioning apparatus, office equipment, a vending machine, and other household apparatuses.

The embodiments of the present invention have been described in detail above referring to the drawings, but the specific configuration is not limited to the embodiments and includes, for example, an amendment to a design that falls within the scope that does not depart from the gist of the present invention. Furthermore, various modifications are possible within the scope of the present invention defined by claims, and embodiments that are made by suitably combining technical means disclosed according to the different embodiments are also included in the technical scope of the present invention. Furthermore, a configuration in which a constituent element that achieves the same effect is substituted for the one that is described according to the embodiments is also included in the technical scope of the present invention.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1 (1A, 1B, 1C) 1 Terminal device     -   3 Base station device     -   10 Radio transmission and/or reception unit     -   11 Antenna unit     -   12 RF unit     -   13 Baseband unit     -   14 Higher layer processing unit     -   15 Medium access control layer processing unit     -   16 Radio resource control layer processing unit     -   30 Radio transmission and/or reception unit     -   31 Antenna unit     -   32 RF unit     -   33 Baseband unit     -   34 Higher layer processing unit     -   35 Medium access control layer processing unit     -   36 Radio resource control layer processing unit 

The invention claimed is:
 1. A terminal device comprising: reception circuitry configured to monitor a Machine type communication Physical Downlink Control CHannel (MPDCCH) in a search space corresponding to a plurality of subframes; and medium access control layer processing circuitry configured to perform a Discontinuous Reception (DRX) functionality for controlling monitoring of the MPDCCH, wherein the medium access control layer processing circuitry starts or restarts a drx-InactivityTimer in a next subframe of a last subframe in the search space, in a case that the MPDCCH indicates initial transmission, the medium access control layer processing circuitry starts a Hybrid Automatic Repeat reQuest (HARQ) Round Trip Time (RTT) timer in a case that the MPDCCH indicates downlink transmission, the HARQ RTT timer is set based on a number of times a Physical Uplink Control CHannel (PUCCH) is repeatedly transmitted, a drx-RetransmissionTimer is started in a case that the HARQ RTT timer expires and data of an HARQ process is not successfully decoded, and the medium access control layer processing circuitry monitors the MPDCCH in an Active Time including a period in which the drx-InactivityTimer or the drx-RetransmissionTimer is running.
 2. A communication method used for a terminal device, the communication method comprising the steps of: monitoring a Machine type communication Physical Downlink Control CHannel (MPDCCH) in a search space corresponding to a plurality of subframes; performing a Discontinuous Reception (DRX) functionality for controlling monitoring of the MPDCCH; starting or restarting a drx-InactivityTimer in a next subframe of a last subframe in the search space in a case that the MPDCCH indicates initial transmission; starting a Hybrid Automatic Repeat reQuest (HARQ) Round Trip Time (RTT) timer in a case that the MPDCCH indicates downlink transmission; setting the HARQ RTT timer based on a number of times a Physical Uplink Control CHannel (PUCCH) is repeatedly transmitted; starting a drx-RetransmissionTimer in a case that the HARQ RTT timer expires and data of an HARQ process is not successfully decoded; and monitoring the MPDCCH in an Active Time including a period in which the drx-InactivityTimer or the drx-RetransmissionTimer is running. 